1.flexible a.易弯曲的，灵活的(elastic)

词根记忆：flex(弯曲)+ible--易弯曲的，灵活的

例：Time management needs to be firexible so that employees can respond to unexpected problems.

2.flip v.轻弹(to flick)；按（开关）(to press a button or switch)；蹦跳a．无礼的 (rude)；冒失的；轻率的(flippant)

联想记忆：f（看作fly飞）+1ip（嘴唇）--飞吻轻抛一无礼的

例：flip over翻页

派生词:flippant(a．轻率的；没礼貌的)

3.flippant a．无礼的(impolite)：轻率的(rude; casually disrespectful)

例：lf your flippant attitude doesn't improve, you're going to be fired.

4.flock n.（鸟、兽等）—群(a group of animals, e.g. birds or sheep etc.)

联想记忆：和block(v.妨碍)一起记

例：a flock of large birds一群大鸟

5.flourish v.繁荣(to thrive, to prosper)；活跃(to be in a period of highest produc-tivity, excellence, or influence)

词根记忆：flour( =flor花)+ish--花一样开放--繁荣

例：People are friendly, the environment is safe, and the arts are flourishing.//This bacterium can flouriish on the dried grain.

6.fluctuate v.(使）涨落,（使）变化(to swing)

词根记忆：fluct(=flu流动)+uate--波动--变化

例：A minority shareholder buys and sells stocks as prices fluctuate over short periods of time.

7.fluctuation n.波动(swing)

词根记忆：来自fluctuate(v.波动)

例：Such fluctuations in population are known as population cycles.

8.fluid n.流体(liquid)；a．流体的，流动的(able to flow freely, as gases and liquids do)

词根记忆：flu(流动)+id--流体；流动的

例：These rats stay in burrows to avoid loss of fluid through panting or sweating.

派生词:fluidounce(n.液量盎司)